Tiger, you are may Hero :thumbup:   
I try to build a home-cockpit since two years. 
Therefor I use the electronic of an keyboard. 
It works nice, but it's not possible to use switches without 
some eletronics (switch 'on' is the same like press down the key :() 
I searched a long time to find a microchip like "yours"   
Now I cell my car, the horse of my girlfriend and build my cockpit :pilotfly: 
yeeehaaaa     
Very nice work :thumbup::thumbup::thumbup:     
Yours     
MadDoc